Courtois Koenig's Model Bb Cornet
Antoine Courtois had the advantage of being born into a brass
instrument making family and he went on to become the most
successful and innovative member.  He established his workshop in
1844 and soon became a specialist in cornets a pistons that were
popular with soloists including Koenig, Arban, Levy and Arbuckle
among many others.  The original Koenig's model was built with
Stoelzel valves (usually called "cornopean" in English) and then with
Perinet valves as in this example by 1855.  
Matthew Arbuckle was
greatly influenced by Koenig when he heard him play in Boston in
the 1860s and eventually switched from his previously favorite Fiske
cornet to one made by Courtois.

This particular cornet had obviously had a very hard life and
restoration work was extensive.  Several parts had to be made
including crooks and the waterkey.  It was then silverplated.  The last
photo below shows another variation of the Koenig's Model Courtois
cornet.  This became the pattern for the Levy's and Arbuckle's
models and copies made by many other makers for decades to come.
 This example retains it's original silver plating, shanks and crooks.   
Both of these cornets are in the collection of Tom Meacham.

Click on images for larger photograph.